Stem Cells and Cloning: Advances and Applications Dovepress open access to scientific and medical research Open Access Full Text Article REVIEW An Overview on Mesenchymal Stem Cells Derived from Extraembryonic Tissues: Supplement Sources and Isolation Methods This article was published in the following Dove Press journal: Stem Cells and Cloning: Advances and Applications Parvin Salehinejad1 Purpose: The main aim of this review was to provide an updated comprehensive report Mojgan Moshrefi2,3 regarding isolation methods of MSCs from human extra embryonic tissues, including cord Touba Eslaminejad4 blood, amniotic fluid, and different parts of the placenta and umbilical cord, with respect to the efficacy of these methods. 1Neuroscience Research Center, Institute of Neuropharmacology, Kerman Results: Extra embryonic tissues are the most available source for harvesting of mesench- University of Medical Sciences, Kerman, ymal stem cells (MSCs). They make a large number of cells accessible using non-invasive 2 Iran; Medical Nanotechnology and methods of isolation and the least immune-rejection reactions. A successful culture of Tissue Engineering Research Center, Yazd Reproductive Science Institute, Shahid primary cells requires obtaining a maximum yield of functional and viable cells from the Sadoughi University of Medical Sciences, tissues. In addition, there are many reports associated with their differentiation into various 3 Yazd, Iran; Research and Clinical Center kinds of cells, and there are some clinical trials regarding their utilization for patients. for Infertility, Yazd Reproductive Science Institute, Shahid Sadoughi University of Conclusion: Currently, cord blood-MSCs have been tested for cartilage and lung diseases. Medical Sciences, Yazd, Iran; Umbilical cord-MSCs were tested for liver and neural disorders. However, these MSCs can 4Pharmaceutics Research Center, be isolated, expanded, and cryopreserved in a cell bank for patients in need. Institute of Neuropharmacology, Kerman University of Medical Sciences, Kerman, Keywords: cord blood-MSCs, umbilical cord-MSCs, amniotic fluid, placenta, embryonic Iran tissues, immune-rejection Introduction Mesenchymal stem cells as connective tissue cells are located in the extracellular matrix (ECM);1 the non-living viscous substance in which cells and fibers belong to the ECM. ECM is a collection of glycoproteins, collagens, laminins, fibronectin, elastin, and proteoglycans, chondroitin, heparan, keratan sulfates, and hyaluronic acid.2 Mesenchymal stem cells are an important cell population, which can possess stem cell-like characteristics.3,4 They are multi-potent, and found in nearly all tissues, mostly located in perivascular niches (Figure 1).5 Perivascular location of the mesench- ymal stem cells (MSCs) correlates them to pericytes.6 Pericytes exist in the wall of the blood vessels, and closely encircle endothelial cells in capillaries, and micro vessels in multiple organs.7 According to this, MSCs can stabilize blood vessels, and contribute to tissue, and immune system homeostasis under physiological conditions. They play a more active role in the repair of damage of the local tissue.8 Since the MSCs have Correspondence: Touba Eslaminejad migratory abilities, they secrete protective factors and act as a primary matrix for tissue Kerman University of Medical Sciences, 5 Kerman, Iran regeneration during inflammation, tissue injuries, and certain cancers. MSCs can Tel +9834331325245 modulate the function of different cells of the immune system, eg, T cells, B cells, Fax +9834331325215 Email [email protected] natural killer cells, and dendritic cells. The in vitro immunomodulatory properties of submit your manuscript | www.dovepress.com Stem Cells and Cloning: Advances and Applications 2020:13 57–65 57 DovePress © 2020 Salehinejad et al. This work is published and licensed by Dove Medical Press Limited. The full terms of this license are available at https://www.dovepress.com/ – http://doi.org/10.2147/SCCAA.S248519 terms.php and incorporate the Creative Commons Attribution Non Commercial (unported, v3.0) License (http://creativecommons.org/licenses/by-nc/3.0/). By accessing the work you hereby accept the Terms. Non-commercial uses of the work are permitted without any further permission from Dove Medical Press Limited, provided the work is properly attributed. For permission for commercial use of this work, please see paragraphs 4.2 and 5 of our Terms (https://www.dovepress.com/terms.php). Salehinejad et al Dovepress and intracellular structures. They are divided into mechanical and chemical methods. Mechanical methods include homo- genizing, sieving, mincing, and affinity. Some of them are traumatic for tissue. This showed that the combination of two methods could be more effective if the mechanical methods are applied immediately before placing into the enzyme. Figure 1 Schematic illustration of mesenchymal stem cells extracted from umbilical Chemical methods are mostly mild, but they have not been cord blood as source multi-potent and found in nearly all tissues. used for the isolation of the cells on a large scale. Chemical methods interact via destroying cell-to-cell attachment by MSCs cause more interest on the potential applications of removal of calcium, and magnesium, separating cell layers them in in vivo assay (as an immunosuppressive cellular by affecting glycine, and changing the pH through suspen- therapy).9 MSCs exhibit a broad differentiation capacity to sion in a buffer solution. Growth factors, eg, epidermal osteoblasts, adipocytes, and chondrocytes, hepatocyte-like growth factor (EGF), Vascular endothelial growth factor cells, neuronal, and neuroglial cells.10 They expressed (VEGF), or fibroblast growth factors (FGF), have been mesenchymal markers such as CD105 and CD90 used as supplements for the in vitro expansion of isolated positively.11 Also MSCs are isolated from a variety of adult MSCs.17 tissues, eg, peripheral blood tissues, adipose tissues, compact bone, dental pulp, and bone marrow, dermis, pancreatic Isolation Methods of Mesenchymal Stem islets, adult brain tissues, skeletal muscle tissues, and syno- Cells vium, circulatory system tissues,7 lung, heart, and hair Human Umbilical Cord Blood follicles.8 Foetal tissues such as liver, lung, and neonatal Umbilical cord blood (UCB) is indicated as a source of tissues including placenta, amnion and different parts of the hematopoietic stem cells which are transplantable for clin- umbilical cord,12 and cord blood5 are used to isolate the ical practice for a decade.18 Because of the small amount of MSCs. As an alternative, stem cell populations could be MSCs, freshly donated UCB does not qualify for harvested at birth.10 In this review, the isolation methods of transplantation.19 The isolated amounts of MSCs are MSCs from different supplement sources were discussed, affected by the volume of a UCB sample as a criterion.20 and also their utilizations in medical application were The volume of the UCB unit and the mononuclear cell count explained. are predictive of the isolation rate of MSCs. The mean volumes of the UCB unit and number of nucleated cells Cell Isolation Protocols per unit are 40 mL and 5.39×108, respectively. But, MSCs Dissociation of the animal cells depends on the age, species, can successfully be isolated from UCB units with a volume tissue origin, and the type of dissociation medium. Tissue of ≥54 mL containing ≥1.28×108 mononuclear cells, which and species factors are not controllable, but mediums and results in a MSC isolation rate of >70%.19 In addition, the conditions associated to tissue dissociation could be con- ratio of cord blood volume/number of nucleated cells is trolled to get the best results.13 Generally, two methods, eg, greater for boy neonates than for girls: 78 mL/12.4×106 enzymatic and non-enzymatic are used for cell isolation. cells from boys compared with the 66.6 mL/10.2×106 har- Enzymes are chosen according to the connective tissue vested cells from the girls.21 Another parameter for success- matrix of the particular organ.14 Enzymes show different ful isolation of the cells is a transporting time of less than 15 impacts on the morphological characteristics of the isolated hours from collection to isolation. However, some research- cells.12 They are applied in simple or cocktail form.15,16 ers believe that the MSC isolation rate is not affected by the Trypsin and collagenase are common enzymes, which are interval between delivery and cell processing.19 To date, at used in cell separation. Furthermore, some characteristics, least three different kinds of stem cells have been isolated eg, kinds of enzymes, amount of impurities in any stock from UCB, including hematopoietic stem cells, endothelial preparation, enzymes’ concentration, and temperature, have progenitor cells, and MSCs.18 MSCs revolve in cord blood a successful influence.13,15,16 but at much lower frequencies than hematopoietic stem Non-enzymatic methods showed advantages over enzy- cells,10 which are 0.002±0.004×106 initially plated cells matic methods, eg, preventing damage to the cell membrane, while the number of MSCs from BM is 83±61×106 initially 58 submit your manuscript | www.dovepress.com Stem Cells and Cloning: Advances and Applications 2020:13 DovePress Dovepress Salehinejad et al plated cells.17 Thus, their isolation and culture are more Amniotic Fluid difficult.10 Generally, MSCs are successfully isolated from Amniotic fluid (AF) MSCs express Oct-4, the pluripotent only 30% to 75% of UCB.8,17,19 marker,